Some international organisations established maximum residue limits (MRLs) in food to protect human health. Mexico lacks regulations in this matter, affecting national and international trade from agroindustry. The aim of this study was to diagnose pesticide residues in oranges from Nuevo Leon, México, in citrus orchards. In May 2014, 100 orange fruit samples were taken randomly from orchards and subjected to analysis for 93 pesticides at residual level by GC/QQQ-MS and LCQ-TOF-MS. Results showed the presence of 15 pesticide residues in the samples. The comparison of the residual levels of pesticides found in orange samples among the MRLs allowed by USA, EU and Japanese regulations demonstrated that all samples were below MRLs issued by USA and Japan. Some orange samples were above MRLs issued by the EU. This provides a basis to establish strategies in order to satisfy International Standards to protect human health and encourage Food Safety in Mexico.

Heavy metals in water are a serious environmental problem due to their accumulation and toxicity; there are several processes we can use to address this issue, but adsorption is the most popular due to its simplicity and efficiency. Polysaccharides such as cellulose have received attention as adsorbents for heavy metals, and cotton–chitosan composites (CCs) were developed here with nontoxic reagents such as carboxylic acids as crosslinkers and NaH2PO4 as a catalyst to achieve chitosan covalent crosslinkage into oxidized cotton textiles with H2O2. The composites were characterized by fourier-transform infrared spectroscopy (FTIR), elemental analysis (EA), X-ray photoelectron spectroscopy (XPS), atomic-force and scanning electron microscopy (AFM and SEM), and tensile strength; the adsorption of lead ions (Pb) was evaluated with cotton–chitosan composites and quantified by microwave plasma atomic emission spectroscopy (MP-AES). The composites showed a maximum incorporation of chitosan of 27.62 mg per gram of cotton textile. A tensile strength analysis of the composite showed a Young’s modulus approximately 1 MPa higher than that of cotton textile. The adsorption of lead ions with composites in an aqueous solution at pH 5 and 25 °C was circa 74% after 6 h of contact, as determined by MP-AES. This work is an approach to demonstrate the potential of these polysaccharides, modified by “green” procedures to remove pollutants from water.

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Palabras clave: hidrocarburos, salud infantil, riesgos, Cadereyta Jiménez RESUMEN El objetivo de este estudio fue evaluar el nivel de exposición a benceno en niños del municipio de Cadereyta Jiménez en Nuevo León, a través de la determinación urinaria de ácido trans, trans-mucónico, compuesto utilizado como biomarcador de exposición a benceno. Nuestros resultados indican que el 28 % de la población rebasa el índice biológico de exposición (500 µg/g CR). Debido a que el benceno se relaciona con neoplasias hematológicas, es necesario emprender estudios para evaluar si existen riesgos hematológicos en niños que viven en zonas con actividad petroquímica.Key words: hydrocarbon, health child, risks, Cadereyta Jiménez ABSTRACTThe aim of this study was to assess the benzene exposure levels in children living in Cadereyta Jiménez in Nuevo León state, through determination of urinary trans, transmuconic acid, a biomarker of benzene exposure. Our results shown that 28 % of the population exceeds the biological exposure index (500 µg/g CR). Considering that benzene is related with hematological malignances it is necessary to undertake studies to assess hematological risks in children living in areas with petrochemical activity.